ML19343D105
| ML19343D105 | |
| Person / Time | |
|---|---|
| Site: | Fermi  |
| Issue date: | 03/26/1981 |
| From: | Wells D DETROIT EDISON CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| EF2-49-962, IEB-80-25, NUDOCS 8104090409 | |
| Download: ML19343D105 (7) | |
Text
.
Detroit Edison niiiBA-March 26,~1981 EF2-49,962 o)
Mr. James G.Keppler, Director-8 Q
Region til U. S. Nuclear Regulatory Commission
,7p,
N 799 Roosevelt Road g7 0,, NO's 73
/Sgk Glen Ellyn, IL 60137 Q4
Dear Mr. Keppler:
D
/,>
Reference:
Enrico Fermi Power Plant, Unit 2 4
USNRC Licensing Docket:
50-341 USNRC IE Bulletin 80-25 (12-19-80)
Subject:
Detroit Edison Response to NRC IE Bulletin 80-25 The enclosed Detroit Edison internal report number EF2-52,500 is herein transmitted to you in response to IE Bul!etin 80-25 The Project Engineering Organization (PEO) for the Enrico Fermi Nuclear Power Plant, Unit 2, has reviewed the unit's safety-related systems with-respect to the operating problems experienced with Target' Rock Safety
]
Relief Valves (SRV's) described in the subject Bulletin.
PE0 has determined that Fermi 2 uses the same type / design valve cited in this Bulletin.
This report commits to an effective program for testing these SRV's.
The Report also states that operating and maintenance procedures will be revised to include the required actions.
Further, the report gives assurance that the SRV pneumatic supply system design concept has been revised to achieve improved system reliability.-
Although some of the actions called for in IEB 80-25 cannot be completed by the requested due date, they will'be completed and reported upon either prior to or during initial startup of Fermi 2.
Should you require additional information from Detroit Edison in this i
matter, please advise us.
Very truly yours, j
Donald A. Wells, Manager Quality Assurance JDR:mb Encl.
3N kPR g104090 M p
r e
Mr. James-G. Keppler March 26, 1981 Page 2 EF2-49,962 The foregoing statements and the enclosed report are based on facts and circumstances-which are true and accurate to the best of my knowledge anc Selief.-
\\s_
d
- 3 PAAntr.n: rt. t'rtr:nT Donald A.fWells,-Managsr Net: y FWY. P
}'[.,
Quality' Assurance
- t. ; c.........
Subscribed aad sworn to before me this <.Jf d day of
't March, 1981, i
- f i
i cc: -Director Division of Reactor Construction inspection
' Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission Washington, DC 20555 Director Division'of Reactor Operations inspection Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission Washington, DC 20555 Director Division of Operating Reactors Office of' Nuclear Reactor Regulation U. S. Nuclear Regulatory. Commission Washington, DC 20555 Mr. Bruce Little, Resident inspector
'U. S. Nuclear Regulatory Commission Resident inspector's_0ffice.
6450 North Dixie Highway Newport, MI 48166
- ~ _
Detroit Edison ENRICO FERf tI NUCLEAR PO' DER PLANT LNIT NO. 2 USNRC LICENSING DOCKET NO.
50-341 SufftARY REPORT E
RESPGNSE TO IE-BULLETIN NO.
80-25 Operating Problems with Target Rock Safety Relief Valves on BWRs Itcrch 11, 1981 (REFERENCE NO.
EF2-52,500)
O RESPONSE TO IE-BULLETIN NO. 80-25 Operating Problems with Target Rock Safety Relief Valves on BWRs INTRODUCTION IE Bulletin 80-25 is addressed to a series of failure events affect-ing the two-stage pilot operated Target Rock safety relief valves at Boston Edison Canpany's Pilgrim Nuclear Power Station - Unit 1.
Fermi 2 has this same type design' valve. One type of malfunction that had occurred, involved failure of an SRV tc open and on another occasion, to close upon manual derand, due to foreign material causing the SRV solenoid and the main stage piston to stick. The other type of malfunction involved the inadvertent opening of an SRV due to overpressurizatica of the pneu:ratic supply which caused leak-age through the SRV solenoid sufficient to open the SRV.
NRC DIRECTIVE IEB 80-25 has directed that BWR plants with operating licenses or near term operating licenses to review their system and take the following action.
1.
For facilities where the SRVs are not presently installed, initiate a Q. C. inspection of the solenoid actuators to verify that they are free frm excessive loc-tite material contamination. For facilities where the SRVs are installed, initiate a full pressure functional test and include in the test report the :.2sults of all attempts to operate each SRV.
2.
Revise operating / maintenance procedures to include the require-ment for any SRV that fails to function as designed, and the malfunction cause has not been clearly identified and corrected, that the entire valve is to be removed, inspected and tested in accordance with the periodic surveillance rehabilitation requirements for these valves.
3.
Relief valve protection is to be provided in close proximity to the SRVs. High and low pressure annunciation for the SRV pneumatic supply is to be provided with the pressure source located as close to the SRVs as practicable. Operating pro-cedures should include operator guidance in responding to a high or low pressure alarm. Consideration should be given to replacing the solenoid operators with a design that can withstand greater pneumatic supply overpressure.
O P 4.
S e review results and intended action on the above three iters are to be reported by the due date. Any corrective modifications are to be conpleted within 6 nonths of the time the decision was made to take this action.
RESPONSE
In response to the action directed, the results of Edison's review, to date, is as follows.
1.
INSPECTION OR FUNCTIONAL TESTING OR SRV SOLENOIDS The Target Ibck Technical Manual for the !bdel 7567F safety relief valves at Fermi 2 cautions against excessive usage of the loc-tite in the assembly of the solenoid valve assenbly.
(Assembly 7567F-010, October 1980, Section 9.1.7 on page 9-4).
We factory assembly inspection procedures are being reviewed to determine if they had already addressed the cautions on excessive use of Ioc tite materials in the manufacturer's written assembly instructions.
Although the Fermi 2 SRVs are not yet installed, they have been completely assenbled ready for installation. To dis-assemble and again irspect these solenoids does offer some risk of exposing them to further contamination and will in-validate all post ass,embly factory Q. C. tests performed pre-viously on these solenoids. Very little will be gained to repeat this factory inspection arxi testing.
%ese valves will be functionally tested by manual initia-tion of the SRV soleroids under the plant "Startup Testing Program." Startup Testing Procedure Ib. 24 for the SRVs will be revised to address the concerns of foreign particles (Ioc-tite) contamination. This will include repeated actua-tions and a report on the results of each actuation.
2.
SRV "MAINIDWJCE INSPTTION PROCEDURES" Cmpletion of the final plant operating and maintenance pro-cedures prior to initial operation, will include instructions that will include the actions called for in IEB 80-25 concern-ing the inspection / overhaul of malfunctioning SRVs.
3.
OVERPRESSURE PROTECTION FOR THE SRV PNELFATIC SUPPLY The SRV pneumatic supply system design concept has been recently revised to achieve inproved system reliability. We detailed engineering on this system revision will soon be initiated and final nodifications will be completed prior to initial opera-tion. This includes equipment changes and operating procedures revisions that address the concerns of IEB 80-25.
- p A review of the latest design concept, that addressed itself to the Pilgrim overpressurization problem, has been performed in response to IE Information Notice 80-40.
This review has shcun that the normal nitrogen supply and backup control air supply to the pneumatic supply system, already have relief valve protection to prevent overpressuri-zation frca exceeding 130 PSIG. This is well below the pressure that must be reached to cause leakage through the present Fermi 2 SRV solenoid valve design. De only other possible source of overpressurization to the pneumatic supply are the emergency nitrogen bottle connections. Although the use of these connections to feed the pneumatic supply system will be very rare,the remote possibility of overpresssuri-zation through these connections will be prevented by additional relief valves on the pneumatic supply piping just ahead of the pneumatic supply prircary containment isolation valves. This will provide protection frco all sources of overpressure, and provides additional redundant protection frce the normal nitro-gen and backup control air sources.
With adequate overpressure protection to prevent the pneumatic supply pressure from reaching high enough levels to cause inadvertent SRV operation, there is no requirement to replace the existing SRV solercid valve design. Until an alternate solenoid valve design, capable of withstanding significantly higher pressures, has been fully tested and qualified to meet the requirements of SRV operation, no attempt to replace the existing design should be considered.
The Fermi 2 SRV pneumatic supply system does have system pressure monitoring and high/ low pressure annunciation in the unit control rocm. Its source is located outside the pri-mary conta.inment. Since all sources for pneumatic supply overpressurization are connected ahead of this source, its location ^.s fully capable of detecting any overpressurization that can impact the SRVs regardless if the containment isola-tion valses are open or closed.
This soulce location will not detect a loss of pneumatic supply to the SIVs and ADS accumulators upon closure of a pneumatic supply coltainment isolation valve. %erefore, valve closure annunciation will be provided in the control rpom to alert the operatar. Valve position indication in the%ntrol rocm is available to provide continuous awareness of the valve position to the operator.
Operating procedures which will be completed prior to initial operation will provide operator guidance in responding to any occurrence of high/ low pneumatic supply pressure or closure of the pnuematic supply containment isolation valves.
--4.
'i C0l41ITl1EN1 Although some of the actions called for in IEB 80-25 cannot be coupleted try the requested due date, they will'be aanpleted and' reported upon.
Prior to and during initial Startup of Fermi 2.
O-O O OOO